That's why you want to get some gear first. I'm sure you can find a cheap pack to get you started. Put an ad on craigslist and see what pops up in the $20-$40 range.

But start assembling gear now. Use what you've got and scrounge and keep an eye out for bargains. For example, you can make a little pack stove for nearly free (the penny stove), and there are a lot of other tips for free and cheap gear. Search the messages and archives and browse the "Make Your Own Gear!" forum here.

Search for messages by member "jasonklass". He's posted some great articles on how to scrounge and make cheap gear.

I doubt you'll need or want a 4500 cu.in pack. I think mine is about 3300 cu.in. I've managed to stuff over 40 lbs into it and that's really more than I should have been carrying. I've reduced that weight by nearly half since learning and following tips here.

Bill